Hemodialysis Devices: Dialysate

Fluid that helps remove uremic waste products such as urea and creatinine, and excess electrolytes such as sodium and potassium from the pts blood it can also replace needed substances such as calcium and bicarbonate to help maintain the bodys acid-base balance

They never mix

Has high concentrations of solutes and excess water.

Dialysate solutions are prescribed to contain desired levels of solutes the pt needs and none of the solutes that must be removed completely.

The dialysate prescription creates the concentration gradient to set up diffusion of certain substances to occur across the dialyzer membrane.

Unwanted solutes leave the blood and move into the dialysate while other wanted solutes remain in the blood

Some solutes such as these are usually included in the dialysate in amounts that can cause them to enter the pts blood.

Begins with a concentrated salt solution (dialysate concentrate) that contains precise amounts of sodium chloride, potassium chloride, magnesium chloride, calcium chloride and in most cases glucose. The salt solution is then buffered with sodium bicarbonate or sodium acetate and diluted with precise amounts of treated water.

Able to neutralize added acids or bases

Is a major electrolyte of the body's interstitial fluid

Sodium causes fluid to move across cell membranes between the intracellular and interstitial spaces, including the intravascular spaces.

Intravascular spaces (inside the blood vessels)

In the blood, it ranges from 135-145 mEq/L and in dialysate, the concentration normally stays around the same. Occasionally, higher sodium concentrations are used, but they require a careful patient assessment and a specific physicians prescription.

In most delivery systems, sodium concentration in dialysate is kept at a constant level throughout the dialysis treatment.

Newer dialysate delivery system allow the sodium concentration to be adjusted throughout the treatment, according to the physicians prescription